Two-way nesting smoothing options

[koszutam]

I am trying to better understand the different options available when opting to use two-way nesting for my nested-domains simulation. The namelist option I am wondering about is called "smooth_option", which has three options: (0) no smoothing, (1) 1-2-1 smoothing, and (2) smoothing-desmooting. I understand that the later 2 are adapted from MM5 but the ARW user guide provides zero information about each option and archived WRF tutorials and the WRF Online Tutorial do not include information on this either. Any resources and insight into how, specifically, option 1 and 2 differ and what exactly no smoothing means (my assumption is that it takes the center grid point from the child domain for its corresponding parent domain). Thank you!

 

[Ming Chen]

I dimly remember that the smooth option is applied to remove short waves. The 1-2-1 method smooths out more wave energy than the smoother-desmoother method. Unfortunately we lost the relevant MM5 documents that describe in detail these smooth options.